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HURRICANE ALBERTO DISCUSSION NUMBER  62
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT SAT AUG 19 2000
 
ALBERTO HAS CONTINUED TO INTENSIFY DESPITE THE LARGE 40 NM DIAMETER
EYE.  SATELLITE ESTIMATES HAVE BEEN NEAR 90 KT FOR THE PAST 6 TO 12
HOURS...SO THE INITIAL INTENSITY HAS BEEN INCREASED.
 
THE INITIAL MOTION IS 360/5.  THERE REMAINS LITTLE CHANGE IN EITHER
THE SYNOPTIC PATTERN OR TO THE FORECAST GUIDANCE FROM THE PAST
SEVERAL ADVISORIES.  ALBERTO IS BEGINNING TO TRACK NORTHWARD AROUND
THE WESTERN SIDE OF A LARGE RIDGE...WHILE A MID- TO UPPER-LEVEL
TROUGH OVER THE NORTHEAST U.S. AND SOUTHEAST CANADA MOVES EAST. THE
ENTIRE TROUGH-RIDGE PATTERN IS FORECAST TO SHIFT EASTWARD THROUGH 48
HOURS AND THIS IS THE MAIN REASON FOR THE SLIGHT NORTHEASTWARD SHIFT
IN THE TRACK. THE SHORTWAVE TROUGH IS NOT EXPECTED TO BEGIN PICKING
UP ALBERTO UNTIL AFTER 48 HOURS...AND THE OFFICIAL TRACK IS CLOSE TO
THE GFDL AND UKMET MODELS...AND THE PREVIOUS FORECAST.

ALBERTO HAS LIKELY PEAKED IN INTENSITY SINCE THE SYSTEM IS NOW
BEGINNING TO MOVE OVER COOLER WATER.  BY 72 HOURS...ALBERTO IS
EXPECTED TO MOVE OVER 20C OR COLDER SSTS WHICH SHOULD HELP TO
RAPIDLY WEAKEN THE SYSTEM...BUT THE INTENSITY WAS HELD SLIGHTLY
HIGHER THAN THE SHIPS MODEL AFTER 48 HOURS.  THIS IS MAINLY DUE TO
THE LARGE SIZE OF THE INNER CORE WIND FIELD WHICH WILL TAKE SOME
TIME TO SPIN DOWN EVEN THOUGH ALBERTO MAY BE DEVOID OF ANY DEEP
CONVECTION IN 72 HOURS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     19/1500Z 36.0N  48.3W    90 KTS
12HR VT     20/0000Z 36.8N  48.4W    90 KTS
24HR VT     20/1200Z 38.2N  48.3W    90 KTS
36HR VT     21/0000Z 39.8N  47.7W    85 KTS
48HR VT     21/1200Z 41.5N  47.0W    75 KTS
72HR VT     22/1200Z 45.3N  44.7W    60 KTS
 
 
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